San Juan leaders question delays in MTBE cleanup

What is MTBE?

MTBE was once added to gasoline throughout the state to help reduce air pollution. It was banned in 2003, but not before it leaked from underground storage tanks statewide, in some cases contaminating water supplies.

The chemical is considered a possible carcinogen. But even at levels too small to be a likely cancer threat, it can lend a foul smell and odor to drinking water.

Orange County MTBE leaks

The first signs of groundwater contamination in Orange County turned up in 1995, though drinking water hasn't been affected. But in Santa Monica, 75 percent of municipal drinking water wells were contaminated. The problem also plagued South Lake Tahoe and other communities.

In the late 1980s, underground storage tanks were reinforced and new technology enabled leak detection systems to be installed.

SAN JUAN CAPISTRANO - City leaders on Tuesday admonished Chevron officials to speed up the cleanup of decade old leaks at two local fuel stations, with the recent discovery of a now-banned gas additive in the community's water supply resulting in the closure of two city wells.

The discovery of methyl tertiary butyl ether has prompted city officials to shut down the Dance Hall well - located near City Hall, at the south end of Paseo Adelanto - and the Kinoshita well - located near Kinoshita Farms, off Camino Del Avion and Alipaz Street. The two wells are among six that feed into the city's groundwater recovery plant.

The cause of the Kinoshita contamination is still under investigation, but the Dancehall contamination has been linked to leaks at two local Chevron stations, located at the intersections of Camino Capistrano and Del Obispo and Ortega Highway and the I-5.

The Orange County Healthcare Agency in March informed the city of the leaks, which Chevron officials say occurred in the late '80s, when the MTBE entered an aquifer under the stations. The aquifer became a source of city water in 2004, when the groundwater recovery plant was constructed.

Chevron officials have tracked the spread of the plume from the Camino Capistrano station south to the Dance Hall well - approximately 1200 to 1300 feet away - but admitted that they do not know how far the plume extends to the east or west. Consulting Chevron Hydrologist Jack Fraim acknowledged that the plumes proximity to pumping wells would likely cause it to move faster.

San Juan officials continued to stress that the amount of MTBE in the wells is well below the level that would pose a health risk to residents, describing the closures as a precautionary measure. The maximum contaminant level allowed under state and federal standards is 13 micrograms per liter, with a contaminant level of 5 micrograms per liter considered safe to drink but aesthetically unappealing. The Kinoshita contaminant level is between 2.9 and 4 micrograms per liter, officials said, with contaminants at the Dance Hall well at 1.3 micrograms per liter.

Chevron officials said that cleanup of the wells would probably not be necessary until the contaminant level reached 5 micrograms per liter, claiming that other community's are using wells with higher contaminant levels than the ones in San Juan. Several council members said the presence of any MTBE was unacceptable.

"I'm not willing to put MTBE into my resident's drinking water purposely," Councilman Lon Uso said. "The longer you run these wells, the higher those MTBE levels will be."

Several council members, as well as a city hired environmental consultant, questioned the speed of Chevron's cleanup efforts.

"For us to have to shut down wells to get their attention is unacceptable," Mayor Joe Soto said.

Chevron had not initially understood the extent of the contamination, Fraim said.

"We were following the plume as we understood it," he said. "We just recently found out it has advanced as far as it did."

Chevron disputed that the Kinoshita contamination was a result of the leaks at their stations, pointing out that a creek and two other city wells - neither of which has tested positive for MTBE - lie between the Dancehall and Kinoshita wells. They claimed that the MTBE could have come from one of 12 other underground tanks in the area.

City officials said the first discovery of MTBE at the Kinoshita occurred a week after the Dance Hall closure. Uso also noted that the Kinoshita well seemed to be located in line with the plumes movement.

Noting the plumes proximity to Trabuco Creek, city leaders also worried that the MTBE has entered the stream bed, although Chevron officials said no indication of such a contamination has been found.

Efforts by Chevron to determine the extent of the MTBE contamination have been hampered by ongoing negotiations with several property owners who have thus far been reticent to allow the company to drill on their properties. If Chevron is unable to get the property owners permission officials said they may need to drill into Del Obispo, one of the city's busiest streets.

City officials said the council will receive monthly updates on the cleanup efforts.

"We're not asking for anything other than making the city whole again," Uso said. "Take out the MTBE you put into our drinking water and we'll be fine."

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